Genetic and population structure of the least shrews Sorex minutissimus in Eurasia

2005年，从保留标本和本人采集的标本中获得的标本如下：芬兰15个标本，挪威1个，堪察加1个，马加丹地区(俄罗斯)4个，普里莫尔斯基5个，哈巴罗夫斯克地区1个，库纳什林岛2个，库纳西里岛1个，萨托贝苏(北海道)11个，Nemuro 5个，滨中町2个，健保岛5个。2006年，我自己捕获了12只来自白鹿町(北海道)、1只来自Sarufutsu-Mura、1只来自蒙古北部。通过采样，获得了对细纹夜蛾栖息地的新认识。Sorex minutissimus是在沙丘和岩石地带捕获的，是其他树种很少使用的。基于线粒体细胞色素b和控制区的序列进行了系统发育研究。欧亚大陆东部和西部的种群在遗传上存在相当大的差异。此外，在东部欧亚人口中，观察到了与地理位置相对应的遗传多样性。北海道种群内的遗传变异很小，而芬兰种群内的遗传变异较大，尽管两者的采样面积几乎相同。北海道种群的低遗传变异可能是最近种群瓶颈事件的结果。芬兰的高变化可能与上一次冰川时代大陆冰盖的发育有关。在最后一次冰河时代，北欧被冰盖覆盖。因此，芬兰细纹夜蛾可能已经撤退到几个避难所，并在变暖后从几个地区返回芬兰，导致了各种单倍型的遗传混合。

In 2005, samples obtained from reserved specimens and those captured by myself is as follows : 15 specimens from Finland, 1 from Norway, 1 from Kamchatka, 4 from Magadan region (Russia), 5 from Primorski, 1 from Khabarovsk region, 2 from Sakhalin, 1 from Kunashiri Island, 11 from Satobetsu (Hokkaido), 5 from Nemuro, 2 from Hamanaka-cho, and 5 from Kenbokki Island. In 2006, 12 shrews from Shiranuka-cho (Hokkaido), 1 from Sarufutsu-mura, and 1 from northern Mongolia were captured by myself. According to the sampling, new knowledge about habitat of Sorex minutissimus was obtained. Sorex minutissimus was captured in sand dune and rocky place, which are rarely used by other shrew species. Thus, it is suggested that S. minutissimus might be pushed to unpreferable habits by other competitively dominant species.Phylogenetic investigation was conducted based on sequences of the mitochondrial cytochrome b and the control region. Populations genetically rather differentiated between the eastern and western parts of Eurasia. In addition, within the eastern Eurasian population, genetic diversification was observed, corresponding to geographic position. There was little genetic variation within Hokkaido population whereas there was much genetic variation within Finnish population although sampling area were almost the same between the two. The low genetic variation in Hokkaido population may be the result of a recent bottleneck event of population. The high variation in Finland may have been related to continental ice sheet development in the last glacial age. In the last glacial age, northern Europe was covered with ice sheet. Thus, Finnish S. minutissimus might have retreated to several refugia and returned to the Finland from several regions after warming, causing a genetic mixture of various haplotypes.